Embodiments of the present invention relate to systems for item orientation and/or item identification.
In a conventional system using radio frequency identification (RFID) for item identification, one or more interrogation units detect and establish communication with one or more RFID devices (e.g., labels or tags). Interrogation units may cooperate with general purpose and special purpose computers to form an integrated system for any business purpose including, for example, security or inventory management. In operation, identification devices are attached to inventory items that then move into and out of communication range. When within the range of a particular interrogation unit, the interrogation unit determines the presence of the tag, determines an identification of the tag, and, based on the processing station at which the particular interrogation unit is associated, and causes particular process steps related to item location to be noted, for example, completion of a receiving, assembly, shipping, purchase, or sale transaction involving the item. In such a system, reliable and accurate detection and identification are highly desirable. When inventories having wide variety are to be managed, it is also highly desirable to utilize a large number of unique identifications. These features present a challenge to system design where the cost of interrogation units and tags are constrained.
Conventional systems, where detection and/or identity is based at least in part on the tag having one or more resonant circuits, fail to provide numerous features which may be desirable in any combination to meet particular system design goals. For example, when a tag includes multiple resonant circuits, it would be desirable (a) to account for manufacturing tolerances, aging, and external de-tuning effects to increase accuracy of detection and identification; (b) to facilitate recognition of an orientation of an item with respect to an interrogation unit; (c) to permit manually altering or supplementing the original identification provided by a tag; (d) to increase the number of identifications with little effect on the cost of manufacturing a tag; (e) to improve the initially manufactured accuracy of resonant circuits; and (f) to increase the speed of factory testing of tags.
Without systems, devices, and methods of the present invention, the above desirable features cannot be easily obtained. Systems that may benefit from or may require some or all of these features may remain economically infeasible, leaving unsatisfied a wide range of potential applications for item and orientation identification technology.
A system for detecting an orientation of a provided responder, according to various aspects of the present invention, includes a receiver and a processor. The receiver is selectively coupled to each antenna of a provided plurality of antennas. The processor is coupled to the receiver for performing a method which includes the steps in any order of: (a) detecting a first response within a first band, detecting being by the receiver via use of a first antenna of the plurality, the first antenna having an antenna field pattern covering a first location; (b) detecting a second response by the receiver via use in turn of each of a multiplicity of antennas of the plurality each having a respective antenna field pattern covering a respective second location; and (c) detecting the orientation of the responder in accordance with indicia of the first location, indicia of the second location, and indicia of an expected relationship between the first location and the second location.
By determining each response with an antenna having an antenna field pattern covering a different location, the relative location of responses may indicate whether the responder is misoriented with respect to the locations. Further communication or further processing of the item identified as misoriented may account for such misorientation, resulting, for example, in improved communication, opportunity for correction of orientation to improve productivity, and improved quality management.
A system for identifying a provided responder, according to various aspects of the present invention, includes a receiver and a processor. The receiver is selectively coupled to each antenna of a provided plurality of antennas. The processor is coupled to the receiver for performing a method which includes the steps in any order of: (a) detecting a first response within a first band, detecting being by the receiver via use of a first antenna of the plurality, the first antenna having an antenna field pattern covering a first location; (b) detecting a second response by the receiver via use in turn of each of a multiplicity of antennas of the plurality each having a respective antenna field pattern covering a respective second location; and (c) determining an identification of the responder in accordance with indicia of the first location, indicia of a particular second location, and indicia of an expected relationship between the first location and the particular second location.
By determining each response with an antenna having an antenna field pattern covering a different location, the relative location of responses may be used as part of the identification of the responder. Because several relative locations are economically feasible in a responder, use of indications of relative location greatly multiply the number of unique identifications a given responder design can accommodate.
A system for identifying a provided responder, according to various aspects of the present invention, includes a receiver and a processor. The receiver is coupled to a provided antenna. The processor is coupled to the receiver for performing a method which includes the steps in any order of: (a) detecting by the receiver a first response within a first band; (b) determining a first frequency offset by comparing a frequency of the first response to a predetermined frequency; (c) determining a second band in accordance with the first frequency offset; (d) determining a third band in accordance with the first frequency offset; (e) detecting by the receiver a second response within the second band; (f) detecting by the receiver a third response within the third band; and (g) determining an identification of the device in accordance with indicia of the second band and indicia of the third band.
By determining the bands for the second and third responses with reference to a frequency offset, internal de-tuning effects (e.g., manufacturing tolerances and aging) and external de-tuning effects (e.g., presence of a metal object in the antenna field pattern of the device) are accounted for.
A responder, according to various aspects of the present invention, includes a plurality of resonant circuits formed on a substrate. Each resonant circuit includes a coiled conductor, a first plurality of capacitors, and a second plurality of capacitors. The coiled conductor is formed on a first side of the substrate and has an interior region surrounded by at least one turn of the coiled conductor and has an exterior region outside the at least one turn. The first plurality of capacitors is formed in the interior region with a dielectric of each capacitor including a respective portion of the substrate. The first plurality of capacitors provides a first capacitance by being selectively decoupled from parallel combination with respect to other capacitors of the first plurality. The second plurality of capacitors is formed in the exterior region with a dielectric of each capacitor including a respective portion of the substrate. The second plurality of capacitors provides a second capacitance by being selectively decoupled from parallel combination with respect to other capacitors of the second plurality. In operation a current flows through a series circuit comprising the first capacitance, the second capacitance, and the coiled conductor. After tuning to a desired resonant frequency of the current, the first capacitance is provided by a first number of capacitors, the second capacitance is provided by a second number of capacitors. The first capacitance is made to be substantially equal to the second capacitance. When equal sized capacitors are used, an absolute value of a difference between the first number and the second number is less than two.
By assuring that the plurality of capacitors located in the interior region provides a capacitance substantially equal to the capacitance provided by the plurality of capacitors located in the exterior region, improved accuracy of resonant frequency and higher resonant circuit quality factor (xe2x80x9cQxe2x80x9d) are obtained during initial manufacturing testing and in operation in the field. When multiple coiled conductors are used (e.g., one on each side of a substrate), each coil may provide substantially the same amount of inductance.
A responder, according to various aspects of the present invention, includes a first substrate and a second substrate. A plurality of functional circuits (e.g., resonant circuits) are provided on the first substrate. For a resonant circuit, each such circuit includes a conductor providing an inductance and a pair of conductors providing a capacitance. The second substrate is mechanically and electrically coupled to the first substrate. The second substrate includes a conductor for modifying a respective function of at least one functional circuit of the plurality on the first substrate. Electrical coupling may be by DC coupling or AC coupling and may modify circuit functions by at least one of enabling a function, modifying an operating characteristic, supplementing operation with a new function, disabling a function, or substituting a new function for an existing function.
Further, a method of establishing an identification for a responder, according to various aspects of the present invention, is performed with respect to a responder that includes a plurality of functional circuits formed on a first substrate. The method includes adhering a second substrate to the first substrate, the second substrate comprising a conductor for modifying a function of at least one circuit of the plurality. The identification of the responder is, therefore, determined in accordance with the respective reactance as modified.
By providing such a responder, tracking of items through check points and process stations is simplified. For example, an inexpensive sticker having a foil or conductive ink component may be used for indicating a quality assurance inspection in a machine readable manner. As another example, an easily modified resonant frequency characteristic of circuit provides additional unique identifications without expensive variation in the initial substrate manufacturing process.